<?php
/**
 * This script lists student attempts
 *
 * @version $Id: report.php,v 1.98.2.46 2009/01/14 07:03:15 tjhunt Exp $
 * @author Martin Dougiamas, Tim Hunt and others.
 * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
 * @package quiz
 *//** */

require_once($CFG->libdir.'/tablelib.php');
require_once($CFG->dirroot.'/mod/quiz/report/overview/overviewsettings_form.php');

class quiz_report extends quiz_default_report {

	/**
	 * Display the report.
	 */
	function display($quiz, $cm, $course) {
		global $CFG, $db;
		// Define some strings
		$strreallydel  = addslashes(get_string('deleteattemptcheck','quiz'));
		$strtimeformat = get_string('strftimedatetime');
		$strreviewquestion = get_string('reviewresponse', 'quiz');

		$context = get_context_instance(CONTEXT_MODULE, $cm->id);

		// Only print headers if not asked to download data
		if (!$download = optional_param('download', NULL)) {
			$this->print_header_and_tabs($cm, $course, $quiz, "overview");
		}

		if($attemptids = optional_param('attemptid', array(), PARAM_INT)) {
			//attempts need to be deleted
			require_capability('mod/quiz:deleteattempts', $context);
			$attemptids = optional_param('attemptid', array(), PARAM_INT);
			foreach($attemptids as $attemptid) {
				add_to_log($course->id, 'quiz', 'delete attempt', 'report.php?id=' . $cm->id,
						$attemptid, $cm->id);
				quiz_delete_attempt($attemptid, $quiz);
			}
			//No need for a redirect, any attemptids that do not exist are ignored.
			//So no problem if the user refreshes and tries to delete the same attempts
			//twice.
		}

		// Work out some display options - whether there is feedback, and whether scores should be shown.
		$hasfeedback = quiz_has_feedback($quiz->id) && $quiz->grade > 1.e-7 && $quiz->sumgrades > 1.e-7;
		$fakeattempt = new stdClass();
		$fakeattempt->preview = false;
		$fakeattempt->timefinish = $quiz->timeopen;
		$reviewoptions = quiz_get_reviewoptions($quiz, $fakeattempt, $context);
		$showgrades = $quiz->grade && $quiz->sumgrades && $reviewoptions->scores;

		$pageoptions = array();
		$pageoptions['id'] = $cm->id;
		$pageoptions['q'] = $quiz->id;
		$pageoptions['mode'] = 'overview';

		/// find out current groups mode
		$currentgroup = groups_get_activity_group($cm, true);

		$reporturl = new moodle_url($CFG->wwwroot.'/mod/quiz/report.php', $pageoptions);
		$qmsubselect = quiz_report_qm_filter_select($quiz);
		$mform = new mod_quiz_report_overview_settings($reporturl, compact('qmsubselect', 'quiz', 'currentgroup'));
		if ($fromform = $mform->get_data()){
			$attemptsmode = $fromform->attemptsmode;
			if ($qmsubselect){
				//control is not on the form if
				//the grading method is not set 
				//to grade one attempt per user eg. for average attempt grade.
				$qmfilter = $fromform->qmfilter;
			} else {
				$qmfilter = 0;
			}
			set_user_preference('quiz_report_overview_detailedmarks', $fromform->detailedmarks);
			set_user_preference('quiz_report_pagesize', $fromform->pagesize);
			$detailedmarks = $fromform->detailedmarks;
			$pagesize = $fromform->pagesize;
		} else {
			$qmfilter = optional_param('qmfilter', 0, PARAM_INT);
			$attemptsmode = optional_param('attemptsmode', QUIZ_REPORT_ATTEMPTS_ALL, PARAM_INT);
			$detailedmarks = get_user_preferences('quiz_report_overview_detailedmarks', 1);
			$pagesize = get_user_preferences('quiz_report_pagesize', 0);
		}
		
		if ($attemptsmode == QUIZ_REPORT_ATTEMPTS_ALL && $currentgroup){
			$attemptsmode = QUIZ_REPORT_ATTEMPTS_STUDENTS_WITH;
		}
		
		if (!$reviewoptions->scores) {
			$detailedmarks = 0;
		}
		if ($pagesize < 1) {
			$pagesize = QUIZ_REPORT_DEFAULT_PAGE_SIZE;
		}
		// We only want to show the checkbox to delete attempts
		// if the user has permissions and if the report mode is showing attempts.
		$candelete = has_capability('mod/quiz:deleteattempts', $context) 
				&& ($attemptsmode!= QUIZ_REPORT_ATTEMPTS_STUDENTS_WITH_NO);


		$displayoptions = array();
		$displayoptions['attemptsmode'] = $attemptsmode;
		$displayoptions['qmfilter'] = $qmfilter;
		$reporturlwithdisplayoptions = new moodle_url($CFG->wwwroot.'/mod/quiz/report.php', $pageoptions + $displayoptions);


		if ($groupmode = groups_get_activity_groupmode($cm)) {   // Groups are being used
			if (!$download) {
				groups_print_activity_menu($cm, $reporturlwithdisplayoptions->out());
			}
		}

		// Print information on the number of existing attempts
		if (!$download) { //do not print notices when downloading
			if ($strattemptnum = quiz_num_attempt_summary($quiz, $cm, true, $currentgroup)) {
				echo '<div class="quizattemptcounts">' . $strattemptnum . '</div>';
			}
		}
		$nostudents = false;
		if (!$students = get_users_by_capability($context, array('mod/quiz:reviewmyattempts', 'mod/quiz:attempt'),'','','','','','',false)){
			notify(get_string('nostudentsyet'));
			$nostudents = true;
			$studentslist = '';
		} else {
			$studentslist = join(',',array_keys($students));
		}
		
		if (empty($currentgroup)) {
			// all users who can attempt quizzes
			$groupstudentslist = '';
			$allowedlist = $studentslist;
		} else {
			// all users who can attempt quizzes and who are in the currently selected group
			if (!$groupstudents = get_users_by_capability($context, 'mod/quiz:attempt','','','','',$currentgroup,'',false)){
				notify(get_string('nostudentsingroup'));
				$nostudents = true;
				$groupstudents = array();
			}
			$groupstudentslist = join(',', array_keys($groupstudents));
			$allowedlist = $groupstudentslist;
		}

		if (!$nostudents || ($attemptsmode == QUIZ_REPORT_ATTEMPTS_ALL)){
	
			// Print information on the grading method and whether we are displaying
			// 
			if (!$download) { //do not print notices when downloading
				if ($strattempthighlight = quiz_report_highlighting_grading_method($quiz, $qmsubselect, $qmfilter)) {
					echo '<div class="quizattemptcounts">' . $strattempthighlight . '</div>';
				}
			}
	
			// Now check if asked download of data
			if ($download) {
				$filename = clean_filename("$course->shortname ".format_string($quiz->name,true));
			}
	
			// Define table columns
			$columns = array();
			$headers = array();
			
	
			if (!$download && $candelete) {
				$columns[]= 'checkbox';
				$headers[]= NULL;
			}
			
			if (!$download && $CFG->grade_report_showuserimage) {
				$columns[]= 'picture';
				$headers[]= '';
			}
	
			$columns[]= 'fullname';
			$headers[]= get_string('name');
	
			if ($CFG->grade_report_showuseridnumber) {
				$columns[]= 'idnumber';
				$headers[]= get_string('idnumber');
			}
			
			$columns[]= 'timestart';
			$headers[]= get_string('startedon', 'quiz');
	
			$columns[]= 'timefinish';
			$headers[]= get_string('timecompleted','quiz');
	
			$columns[]= 'duration';
			$headers[]= get_string('attemptduration', 'quiz');
	
			if ($showgrades) {
				$columns[] = 'sumgrades';
				$headers[] = get_string('grade', 'quiz').'/'.$quiz->grade;
			}
	
			if ($detailedmarks) {
				// we want to display marks for all questions
				$questions = quiz_report_load_questions($quiz);
				foreach ($questions as $id => $question) {
					// Ignore questions of zero length
					$columns[] = 'qsgrade'.$id;
					$headers[] = '#'.$question->number;
				}
			}
	
			if ($hasfeedback) {
				$columns[] = 'feedbacktext';
				$headers[] = get_string('feedback', 'quiz');
			}
	
			if (!$download) {
				// Set up the table
	
				$table = new flexible_table('mod-quiz-report-overview-report');
	
				$table->define_columns($columns);
				$table->define_headers($headers);
				$table->define_baseurl($reporturlwithdisplayoptions->out());
	
				$table->sortable(true);
				$table->collapsible(true);
	
				$table->column_suppress('picture');
				$table->column_suppress('fullname');
				$table->column_suppress('idnumber');
				
				$table->no_sorting('feedbacktext');
	
				$table->column_class('picture', 'picture');
				$table->column_class('fullname', 'bold');
				$table->column_class('sumgrades', 'bold');
	
				$table->set_attribute('cellspacing', '0');
				$table->set_attribute('id', 'attempts');
				$table->set_attribute('class', 'generaltable generalbox');
	
				// Start working -- this is necessary as soon as the niceties are over
				$table->setup();
			} else if ($download =='ODS') {
				require_once("$CFG->libdir/odslib.class.php");
	
				$filename .= ".ods";
				// Creating a workbook
				$workbook = new MoodleODSWorkbook("-");
				// Sending HTTP headers
				$workbook->send($filename);
				// Creating the first worksheet
				$sheettitle = get_string('reportoverview','quiz');
				$myxls =& $workbook->add_worksheet($sheettitle);
				// format types
				$format =& $workbook->add_format();
				$format->set_bold(0);
				$formatbc =& $workbook->add_format();
				$formatbc->set_bold(1);
				$formatbc->set_align('center');
				$formatb =& $workbook->add_format();
				$formatb->set_bold(1);
				$formaty =& $workbook->add_format();
				$formaty->set_bg_color('yellow');
				$formatc =& $workbook->add_format();
				$formatc->set_align('center');
				$formatr =& $workbook->add_format();
				$formatr->set_bold(1);
				$formatr->set_color('red');
				$formatr->set_align('center');
				$formatg =& $workbook->add_format();
				$formatg->set_bold(1);
				$formatg->set_color('green');
				$formatg->set_align('center');
				// Here starts workshhet headers
	
				$colnum = 0;
				foreach ($headers as $item) {
					$myxls->write(0,$colnum,$item,$formatbc);
					$colnum++;
				}
				$rownum=1;
			} else if ($download =='Excel') {
				require_once("$CFG->libdir/excellib.class.php");
	
				$filename .= ".xls";
				// Creating a workbook
				$workbook = new MoodleExcelWorkbook("-");
				// Sending HTTP headers
				$workbook->send($filename);
				// Creating the first worksheet
				$sheettitle = get_string('reportoverview','quiz');
				$myxls =& $workbook->add_worksheet($sheettitle);
				// format types
				$format =& $workbook->add_format();
				$format->set_bold(0);
				$formatbc =& $workbook->add_format();
				$formatbc->set_bold(1);
				$formatbc->set_align('center');
				$formatb =& $workbook->add_format();
				$formatb->set_bold(1);
				$formaty =& $workbook->add_format();
				$formaty->set_bg_color('yellow');
				$formatc =& $workbook->add_format();
				$formatc->set_align('center');
				$formatr =& $workbook->add_format();
				$formatr->set_bold(1);
				$formatr->set_color('red');
				$formatr->set_align('center');
				$formatg =& $workbook->add_format();
				$formatg->set_bold(1);
				$formatg->set_color('green');
				$formatg->set_align('center');
	
				$colnum = 0;
				foreach ($headers as $item) {
					$myxls->write(0,$colnum,$item,$formatbc);
					$colnum++;
				}
				$rownum=1;
			} else if ($download=='CSV') {
				$filename .= ".txt";
	
				header("Content-Type: application/download\n");
				header("Content-Disposition: attachment; filename=\"$filename\"");
				header("Expires: 0");
				header("Cache-Control: must-revalidate,post-check=0,pre-check=0");
				header("Pragma: public");
	
				echo implode("\t", $headers)." \n";
			}
	
	
			// Construct the SQL
			$select = 'SELECT '.sql_concat('u.id', '\'#\'', $db->IfNull('qa.attempt', '0')).' AS uniqueid, ';
			if ($qmsubselect) {
				$select .=
					"(CASE " .
					"   WHEN $qmsubselect THEN 1" .
					"   ELSE 0 " .
					"END) AS gradedattempt, ";
			}
			
			$select .='qa.uniqueid AS attemptuniqueid, qa.id AS attempt, u.id AS userid, u.idnumber, u.firstname, u.lastname, u.picture, '.
				'qa.sumgrades, qa.timefinish, qa.timestart, qa.timefinish - qa.timestart AS duration ';
	
			// This part is the same for all cases - join users and quiz_attempts tables
			$from = 'FROM '.$CFG->prefix.'user u ';
			$from .= 'LEFT JOIN '.$CFG->prefix.'quiz_attempts qa ON qa.userid = u.id AND qa.quiz = '.$quiz->id;
			if ($qmsubselect && $qmfilter){
				$from .= ' AND '.$qmsubselect;
			}
			switch ($attemptsmode){
				case QUIZ_REPORT_ATTEMPTS_ALL:
					// Show all attempts, including students who are no longer in the course
					$where = ' WHERE qa.id IS NOT NULL AND qa.preview = 0';
					break;
				case QUIZ_REPORT_ATTEMPTS_STUDENTS_WITH:
					// Show only students with attempts
					$where = ' WHERE u.id IN (' .$allowedlist. ') AND qa.preview = 0 AND qa.id IS NOT NULL';
					break;
				case QUIZ_REPORT_ATTEMPTS_STUDENTS_WITH_NO:
					// Show only students without attempts
					$where = ' WHERE u.id IN (' .$allowedlist. ') AND qa.id IS NULL';
					break;
				case QUIZ_REPORT_ATTEMPTS_ALL_STUDENTS:
					// Show all students with or without attempts
					$where = ' WHERE u.id IN (' .$allowedlist. ') AND (qa.preview = 0 OR qa.preview IS NULL)';
					break;
			}
	
			$countsql = 'SELECT COUNT(DISTINCT('.sql_concat('u.id', '\'#\'', 'COALESCE(qa.attempt, 0)').')) '.$from.$where;
	
			
			// Add table joins so we can sort by question grade
			// unfortunately can't join all tables necessary to fetch all grades
			// to get the state for one question per attempt row we must join two tables
			// and there is a limit to how many joins you can have in one query. In MySQL it
			// is 61. This means that when having more than 29 questions the query will fail.
			// So we join just the tables needed to sort the attempts.
			if(!$download && $sort = $table->get_sql_sort()) {
				if (!$download && $detailedmarks) {
					$from .= ' ';
					$sortparts	= explode(',', $sort);
					$matches = array();
					foreach($sortparts as $sortpart) {
						$sortpart = trim($sortpart);
						if (preg_match('/^qsgrade([0-9]+)/', $sortpart, $matches)){
							$qid = intval($matches[1]);
							$select .=  ", qs$qid.grade AS qsgrade$qid, qs$qid.event AS qsevent$qid, qs$qid.id AS qsid$qid";
							$from .= "LEFT JOIN {$CFG->prefix}question_sessions qns$qid ON qns$qid.attemptid = qa.uniqueid AND qns$qid.questionid = $qid ";
							$from .=  "LEFT JOIN  {$CFG->prefix}question_states qs$qid ON qs$qid.id = qns$qid.newgraded ";
						} else {
							$newsort[] = $sortpart;
						}
					}
					$select .= ' ';
				}
			}
		   
	
			if ($download){
				$sort = '';
			}
			// Fix some wired sorting
			if (empty($sort)) {
				$sort = ' ORDER BY uniqueid';
			} else {
				$sort = ' ORDER BY '.$sort;
			}
	
			if (!$download) {
				// Add extra limits due to initials bar
				if($table->get_sql_where()) {
					$where .= ' AND '.$table->get_sql_where();
				}
	
				if (!empty($countsql)) {
					$totalinitials = count_records_sql($countsql);
					if ($table->get_sql_where()) {
						$countsql .= ' AND '.$table->get_sql_where();
					}
					$total  = count_records_sql($countsql);
	
				}
	
				$table->pagesize($pagesize, $total);
			}
	
			// Fetch the attempts
			if (!$download) {
				$attempts = get_records_sql($select.$from.$where.$sort,
										$table->get_page_start(), $table->get_page_size());
			} else {
				$attempts = get_records_sql($select.$from.$where.$sort);
			}
			
			// Build table rows
			if (!$download) {
				$table->initialbars($totalinitials>20);
			}
			if ($attempts) {
				if($detailedmarks) {
					//get all the attempt ids we want to display on this page
					//or to export for download.
					$attemptids = array();
					foreach ($attempts as $attempt){
						if ($attempt->attemptuniqueid > 0){
							$attemptids[] = $attempt->attemptuniqueid;
						}
					}
					$gradedstatesbyattempt = quiz_get_newgraded_states($attemptids, true, 'qs.id, qs.grade, qs.event, qs.question, qs.attempt');
				}
				foreach ($attempts as $attempt) {
	
					// Username columns.
					$row = array();
					if (in_array('checkbox', $columns)){
						if ($attempt->attempt){
							$row[] = '<input type="checkbox" name="attemptid[]" value="'.$attempt->attempt.'" />';
						} else {
							$row[] = '';
						}
					}
					if (in_array('picture', $columns)){
						$picture = print_user_picture($attempt->userid, $course->id, $attempt->picture, false, true);
						$row[] = $picture;
					}
					if (!$download){
						$userlink = '<a href="'.$CFG->wwwroot.'/user/view.php?id='.$attempt->userid.
								'&amp;course='.$course->id.'">'.fullname($attempt).'</a>';
						$row[] = $userlink;
					} else {
						$row[] = fullname($attempt);
					}
					
					if (in_array('idnumber', $columns)){
						$row[] = $attempt->idnumber;
					}
	
					// Timing columns.
					if ($attempt->attempt) {
						$startdate = userdate($attempt->timestart, $strtimeformat);
						if (!$download) {
							$row[] = '<a href="review.php?q='.$quiz->id.'&amp;attempt='.$attempt->attempt.'">'.$startdate.'</a>';
						} else {
							$row[] = $startdate;
						}
						if ($attempt->timefinish) {
							$timefinish = userdate($attempt->timefinish, $strtimeformat);
							$duration = format_time($attempt->duration);
							if (!$download) {
								$row[] = '<a href="review.php?q='.$quiz->id.'&amp;attempt='.$attempt->attempt.'">'.$timefinish.'</a>';
							} else {
								$row[] = $timefinish;
							}
							$row[] = $duration;
						} else {
							$row[] = '-';
							$row[] = get_string('unfinished', 'quiz');
						}
					} else {
						$row[] = '-';
						$row[] = '-';
						$row[] = '-';
					}
	
					// Grades columns.
					if ($showgrades) {
						if ($attempt->timefinish) {
							$grade = quiz_rescale_grade($attempt->sumgrades, $quiz);
							if (!$download) {
								$gradehtml = '<a href="review.php?q='.$quiz->id.'&amp;attempt='.$attempt->attempt.'">'.$grade.'</a>';
								if ($qmsubselect && $attempt->gradedattempt){
									$gradehtml = '<div class="highlight">'.$gradehtml.'</div>';
								}
								$row[] = $gradehtml;
							} else {
								$row[] = $grade;
							}
						} else {
							$row[] = '-';
						}
						
					}
	
					if($detailedmarks) {
						if(empty($attempt->attempt)) {
							foreach($questions as $question) {
								$row[] = '-';
							}
						} else {
							foreach($questions as $questionid => $question) {
								$stateforqinattempt = $gradedstatesbyattempt[$attempt->attemptuniqueid][$questionid];
								if (question_state_is_graded($stateforqinattempt)) {
									$grade = quiz_rescale_grade($stateforqinattempt->grade, $quiz);
								} else {
									$grade = '--';
								}
								if (!$download) {
									$grade = $grade.'/'.quiz_rescale_grade($question->grade, $quiz);
									$row[] = link_to_popup_window('/mod/quiz/reviewquestion.php?state='.
											$stateforqinattempt->id.'&amp;number='.$question->number,
											'reviewquestion', $grade, 450, 650, $strreviewquestion, 'none', true);
								} else {
									$row[] = $grade;
								}
							}
						}
					}
	
					// Feedback column.
					if ($hasfeedback) {
						if ($attempt->timefinish) {
							$row[] = quiz_report_feedback_for_grade(quiz_rescale_grade($attempt->sumgrades, $quiz), $quiz->id);
						} else {
							$row[] = '-';
						}
					}
					if (!$download) {
						$table->add_data($row);
					} else if ($download == 'Excel' or $download == 'ODS') {
						$colnum = 0;
						foreach($row as $item){
							$myxls->write($rownum,$colnum,$item,$format);
							$colnum++;
						}
						$rownum++;
					} else if ($download=='CSV') {
						$text = implode("\t", $row);
						echo $text." \n";
					}
				}
				//end of adding data from attempts data to table / download
				//now add averages :
				if (!$download && $attempts){
		
					$averagesql = "SELECT AVG(qg.grade) AS grade " .
							"FROM {$CFG->prefix}quiz_grades qg " .
							"WHERE quiz=".$quiz->id;
							
					$table->add_separator();
					if ($groupstudentslist){
						$groupaveragesql = $averagesql." AND qg.userid IN ($groupstudentslist)";
						$groupaverage = get_record_sql($groupaveragesql);
						$groupaveragerow = array('fullname' => get_string('groupavg', 'grades'),
								'sumgrades' => round($groupaverage->grade, $quiz->decimalpoints),
								'feedbacktext'=> quiz_report_feedback_for_grade($groupaverage->grade, $quiz->id));
						if($detailedmarks && $qmsubselect) {
							$avggradebyq = quiz_get_average_grade_for_questions($quiz, $groupstudentslist);
							$groupaveragerow += quiz_format_average_grade_for_questions($avggradebyq, $questions, $quiz, $download);
						}
						$table->add_data_keyed($groupaveragerow);
					}
					$overallaverage = get_record_sql($averagesql." AND qg.userid IN ($studentslist)");
					$overallaveragerow = array('fullname' => get_string('overallaverage', 'grades'),
								'sumgrades' => round($overallaverage->grade, $quiz->decimalpoints),
								'feedbacktext'=> quiz_report_feedback_for_grade($overallaverage->grade, $quiz->id));
					if($detailedmarks && $qmsubselect) {
						$avggradebyq = quiz_get_average_grade_for_questions($quiz, $studentslist);
						$overallaveragerow += quiz_format_average_grade_for_questions($avggradebyq, $questions, $quiz, $download);
					}
					$table->add_data_keyed($overallaveragerow);
				}	
				if (!$download) {
					// Start form
					echo '<div id="tablecontainer">';
					echo '<form id="attemptsform" method="post" action="' . $reporturlwithdisplayoptions->out(true) .
							'" onsubmit="return confirm(\''.$strreallydel.'\');">';
					echo '<div style="display: none;">';
					echo $reporturlwithdisplayoptions->hidden_params_out();
					echo '</div>';
					echo '<div>';
	
					// Print table
					$table->print_html();
	
					// Print "Select all" etc.
					if (!empty($attempts) && $candelete) {
						echo '<table id="commands">';
						echo '<tr><td>';
						echo '<a href="javascript:select_all_in(\'DIV\',null,\'tablecontainer\');">'.
								get_string('selectall', 'quiz').'</a> / ';
						echo '<a href="javascript:deselect_all_in(\'DIV\',null,\'tablecontainer\');">'.
								get_string('selectnone', 'quiz').'</a> ';
						echo '&nbsp;&nbsp;';
						echo '<input type="submit" value="'.get_string('deleteselected', 'quiz_overview').'"/>';
						echo '</td></tr></table>';
					}
					// Close form
					echo '</div>';
					echo '</form></div>';
	
					if (!empty($attempts)) {
						echo '<table class="boxaligncenter"><tr>';
						echo '<td>';
						print_single_button($reporturl->out(true), $pageoptions + $displayoptions + array('download' => 'ODS'),
											 get_string('downloadods'));
						echo "</td>\n";
						echo '<td>';
						print_single_button($reporturl->out(true), $pageoptions + $displayoptions + array('download' => 'Excel'),
											 get_string('downloadexcel'));
						echo "</td>\n";
						echo '<td>';
						print_single_button($reporturl->out(true), $pageoptions + $displayoptions + array('download' => 'CSV'),
											 get_string('downloadtext'));
						echo "</td>\n";
						echo "<td>";
						helpbutton('overviewdownload', get_string('overviewdownload', 'quiz_overview'), 'quiz');
						echo "</td>\n";
						echo '</tr></table>';
					}
				}
			} else {
				if (!$download) {
					$table->print_html();
				}
			}
			if ($download == 'Excel' or $download == 'ODS') {
				$workbook->close();
				exit;
			} else if ($download == 'CSV') {
				exit;
			}
		}
		if (!$download) {
			// Print display options
			$mform->set_data($displayoptions +compact('detailedmarks', 'pagesize'));
			$mform->display();
			//should be quicker than a COUNT to test if there is at least one record :
			if ($showgrades && get_records('quiz_grades', 'quiz', $quiz->id, '', '*', 0, 1)){
				$imageurl = $CFG->wwwroot.'/mod/quiz/report/overview/overviewgraph.php?id='.$quiz->id;
				print_heading(get_string('overviewreportgraph', 'quiz_overview'));
				echo '<div class="mdl-align"><img src="'.$imageurl.'" alt="'.get_string('overviewreportgraph', 'quiz_overview').'" /></div>';
			}
		}
		return true;
	}
}

?>
